Synthetic wollastonite

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil microorganisms

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with column 2 of Annex IX (Section 9.4.2) of REACH Regulation 1907/2006 toxicity testing may be required if direct and indirect exposure of the soil compartment is likely.
The substance consists of amorphous and crystalline silica which when released into the environment are expected to combine indistinguishably with the soil or sediment due to their similarity with inorganic soil/sediment matter and will be subjected to natural processes under environmental conditions (cation exchange, dissolution, sedimentation). It is therefore considered to be essentially a mineral fraction of soil already. For this reason it is considered that the performance toxicity tests on soil micro-organisms is not scientifically justified.

Testing was carried out on the read-across material Kieselguhr soda ash flux calcined at 3 trophic levels (algae, daphnia and fish) in reliable OECD guideline studies. In each study the L(E)C50s were greater than the solubility of the substance (ie 100% v/v saturated solution).
Based on these results the substance is considered to have no/low toxicity.
The substance was negative in an in vitro bacterial reverse mutation assay using Salmonella typhimurium TA 1538, TA1535, TA1537, TA98 and TA100 with and without metabolic activation. There was no evidence of cytotoxicity.

Reason / purpose for cross-reference:

data waiving: supporting information

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data waiving: supporting information

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data waiving: supporting information

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data waiving: supporting information

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data waiving: supporting information

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data waiving: supporting information

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data waiving: supporting information

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data waiving: supporting information

Description of key information

A study with Synthetic wollastonite has not been conducted as there are no concerns in regard to direct and indirect exposure of the soil compartment. The substance is considered to have no or very low toxicity based on a number of studies.

The substance consists of amorphous and crystalline silica which when released into the environment are expected to combine indistinguishably with the soil or sediment due to their similarity with inorganic soil/sediment matter and will be subjected to natural processes under environmental conditions (cation exchange, dissolution, sedimentation). It is therefore considered to be essentially a mineral fraction of soil already. For this reason it is considered that the performance of toxicity tests on soil micro organisms is not scientifically justified.